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Biomedicines Mar 2024The choroid plexus (CP) plays significant roles in secreting cerebrospinal fluid (CSF) and forming circadian rhythms. A monolayer of epithelial cells with tight and... (Review)
Review
The choroid plexus (CP) plays significant roles in secreting cerebrospinal fluid (CSF) and forming circadian rhythms. A monolayer of epithelial cells with tight and adherens junctions of CP forms the blood-CSF barrier to control the movement of substances between the blood and ventricles, as microvessels in the stroma of CP have fenestrations in endothelial cells. CP epithelial cells are equipped with several kinds of transporters and ion channels to transport nutrient substances and secrete CSF. In addition, junctional components also contribute to CSF production as well as blood-CSF barrier formation. However, it remains unclear how junctional components as well as transporters and ion channels contribute to the pathogenesis of neurodegenerative disorders. In this manuscript, recent findings regarding the distribution and significance of transporters, ion channels, and junctional proteins in CP epithelial cells are introduced, and how changes in expression of their epithelial proteins contribute to the pathophysiology of brain disorders are reviewed.
PubMed: 38672064
DOI: 10.3390/biomedicines12040708 -
Symmetry Aug 2023Planar polarity is a commonly observed phenomenon in which proteins display a consistent asymmetry in their subcellular localization or activity across the plane of a...
Planar polarity is a commonly observed phenomenon in which proteins display a consistent asymmetry in their subcellular localization or activity across the plane of a tissue. During animal development, planar polarity is a fundamental mechanism for coordinating the behaviors of groups of cells to achieve anisotropic tissue remodeling, growth, and organization. Therefore, a primary focus of developmental biology research has been to understand the molecular mechanisms underlying planar polarity in a variety of systems to identify conserved principles of tissue organization. In the early embryo, the germband neuroectoderm epithelium rapidly doubles in length along the anterior-posterior axis through a process known as convergent extension (CE); it also becomes subdivided into tandem tissue compartments through the formation of compartment boundaries (CBs). Both processes are dependent on the planar polarity of proteins involved in cellular tension and adhesion. The enrichment of actomyosin-based tension and adherens junction-based adhesion at specific cell-cell contacts is required for coordinated cell intercalation, which drives CE, and the creation of highly stable cell-cell contacts at CBs. Recent studies have revealed a system for rapid cellular polarization triggered by the expression of leucine-rich-repeat (LRR) cell-surface proteins in striped patterns. In particular, the non-uniform expression of Toll-2, Toll-6, Toll-8, and Tartan generates local cellular asymmetries that allow cells to distinguish between cell-cell contacts oriented parallel or perpendicular to the anterior-posterior axis. In this review, we discuss (1) the biomechanical underpinnings of CE and CB formation, (2) how the initial symmetry-breaking events of anterior-posterior patterning culminate in planar polarity, and (3) recent advances in understanding the molecular mechanisms downstream of LRR receptors that lead to planar polarized tension and junctional adhesion.
PubMed: 38650964
DOI: 10.3390/sym15081490 -
Cellular and Molecular Biology... Mar 2024This study aimed to explore the core genes of craniopharyngioma angiogenesis for targeted vascular therapy based on single-cell nuclear transcriptome sequencing. For...
This study aimed to explore the core genes of craniopharyngioma angiogenesis for targeted vascular therapy based on single-cell nuclear transcriptome sequencing. For single-cell nuclear transcriptome sequencing, we collected six samples from the tumor center and adjacent hypothalamic tumor tissues from three patients with craniopharyngioma, as well as four normal brain tissues based on Gene Expression Omnibus. We screened genes with differential up-regulation between vascular endothelial cells of craniopharyngioma and those of normal brain tissues, performed GO and KEGG analysis, constructed the protein-protein interaction network, and selected key genes verified using immunofluorescence. After data cleaning and quality control, 623 craniopharyngioma endothelial cells and 439 healthy brain endothelial cells were obtained. Compared with normal brain endothelial cells, craniopharyngioma endothelial cells were screened for 394 differentially up-expressed genes (DEGs). GO and KEGG results showed that DEGs probably modulated endothelial cells, adherens junction, focal adhesion, migration, actin cytoskeleton, and invasion via the PI3K-AKT, Rap1, Ras, Wnt, and Hippo pathways. The core genes screened were CTNNB1, PTK2, ITGB1, STAT3, FYN, HIF1A, VCL, SMAD3, PECAM1, FOS, and CDH5. This study obtained possible anti-angiogenic genes in craniopharyngioma. Our results shed novel insights into molecular mechanisms and craniopharyngioma treatment.
Topics: Humans; Craniopharyngioma; Neovascularization, Pathologic; Single-Cell Analysis; Transcriptome; Gene Expression Regulation, Neoplastic; Gene Expression Profiling; Protein Interaction Maps; Pituitary Neoplasms; Endothelial Cells; Gene Regulatory Networks; Angiogenesis
PubMed: 38650143
DOI: 10.14715/cmb/2024.70.3.20 -
Cancer Cell May 2024Monocyte-derived tumor-associated macrophages (Mo-TAMs) intensively infiltrate diffuse gliomas with remarkable heterogeneity. Using single-cell transcriptomics, we chart...
Monocyte-derived tumor-associated macrophages (Mo-TAMs) intensively infiltrate diffuse gliomas with remarkable heterogeneity. Using single-cell transcriptomics, we chart a spatially resolved transcriptional landscape of Mo-TAMs across 51 patients with isocitrate dehydrogenase (IDH)-wild-type glioblastomas or IDH-mutant gliomas. We characterize a Mo-TAM subset that is localized to the peri-necrotic niche and skewed by hypoxic niche cues to acquire a hypoxia response signature. Hypoxia-TAM destabilizes endothelial adherens junctions by activating adrenomedullin paracrine signaling, thereby stimulating a hyperpermeable neovasculature that hampers drug delivery in glioblastoma xenografts. Accordingly, genetic ablation or pharmacological blockade of adrenomedullin produced by Hypoxia-TAM restores vascular integrity, improves intratumoral concentration of the anti-tumor agent dabrafenib, and achieves combinatorial therapeutic benefits. Increased proportion of Hypoxia-TAM or adrenomedullin expression is predictive of tumor vessel hyperpermeability and a worse prognosis of glioblastoma. Our findings highlight Mo-TAM diversity and spatial niche-steered Mo-TAM reprogramming in diffuse gliomas and indicate potential therapeutics targeting Hypoxia-TAM to normalize tumor vasculature.
Topics: Humans; Glioblastoma; Animals; Adrenomedullin; Mice; Brain Neoplasms; Tumor-Associated Macrophages; Neovascularization, Pathologic; Tumor Microenvironment; Isocitrate Dehydrogenase; Xenograft Model Antitumor Assays; Cell Line, Tumor; Macrophages; Cell Hypoxia
PubMed: 38640932
DOI: 10.1016/j.ccell.2024.03.013 -
Developmental Cell Jun 2024Epithelial remodeling of the Drosophila retina depends on the pulsatile contraction and expansion of apical contacts between the cells that form its hexagonal lattice....
Epithelial remodeling of the Drosophila retina depends on the pulsatile contraction and expansion of apical contacts between the cells that form its hexagonal lattice. Phosphoinositide PI(3,4,5)P (PIP) accumulates around tricellular adherens junctions (tAJs) during contact expansion and dissipates during contraction, but with unknown function. Here, we found that manipulations of Pten or PI3-kinase (PI3K) that either decreased or increased PIP resulted in shortened contacts and a disordered lattice, indicating a requirement for PIP dynamics and turnover. These phenotypes are caused by a loss of branched actin, resulting from impaired activity of the Rac1 Rho GTPase and the WAVE regulatory complex (WRC). We additionally found that during contact expansion, PI3K moves into tAJs to promote the cyclical increase of PIP in a spatially and temporally precise manner. Thus, dynamic control of PIP by Pten and PI3K governs the protrusive phase of junctional remodeling, which is essential for planar epithelial morphogenesis.
Topics: Animals; PTEN Phosphohydrolase; Drosophila Proteins; Actins; Morphogenesis; Phosphatidylinositol Phosphates; Phosphatidylinositol 3-Kinases; Adherens Junctions; Retina; Drosophila melanogaster; rac1 GTP-Binding Protein
PubMed: 38640926
DOI: 10.1016/j.devcel.2024.03.035 -
BMC Genomics Apr 2024Fatty liver hemorrhagic syndrome (FLHS) in the modern poultry industry is primarily caused by nutrition. Despite encouraging progress on FLHS, the mechanism through...
BACKGROUND
Fatty liver hemorrhagic syndrome (FLHS) in the modern poultry industry is primarily caused by nutrition. Despite encouraging progress on FLHS, the mechanism through which nutrition influences susceptibility to FLHS is still lacking in terms of epigenetics.
RESULTS
In this study, we analyzed the genome-wide patterns of trimethylated lysine residue 27 of histone H3 (H3K27me3) enrichment by chromatin immunoprecipitation-sequencing (ChIP-seq), and examined its association with transcriptomes in healthy and FLHS hens. The study results indicated that H3K27me3 levels were increased in the FLHS hens on a genome-wide scale. Additionally, H3K27me3 was found to occupy the entire gene and the distant intergenic region, which may function as silencer-like regulatory elements. The analysis of transcription factor (TF) motifs in hypermethylated peaks has demonstrated that 23 TFs are involved in the regulation of liver metabolism and development. Transcriptomic analysis indicated that differentially expressed genes (DEGs) were enriched in fatty acid metabolism, amino acid, and carbohydrate metabolism. The hub gene identified from PPI network is fatty acid synthase (FASN). Combined ChIP-seq and transcriptome analysis revealed that the increased H3K27me3 and down-regulated genes have significant enrichment in the ECM-receptor interaction, tight junction, cell adhesion molecules, adherens junction, and TGF-beta signaling pathways.
CONCLUSIONS
Overall, the trimethylation modification of H3K27 has been shown to have significant regulatory function in FLHS, mediating the expression of crucial genes associated with the ECM-receptor interaction pathway. This highlights the epigenetic mechanisms of H3K27me3 and provides insights into exploring core regulatory targets and nutritional regulation strategies in FLHS.
Topics: Animals; Female; Diet, Protein-Restricted; Histones; Chickens; Epigenesis, Genetic; Fatty Liver; Hemorrhage; Transcriptome; Abnormalities, Multiple; Growth Disorders; Heart Septal Defects, Ventricular; Craniofacial Abnormalities
PubMed: 38627644
DOI: 10.1186/s12864-024-10270-w -
Zebrafish Apr 2024Tjp1a and other tight junction and adherens proteins play important roles in cell-cell adhesion, scaffolding, and forming seals between cells in epithelial and...
Tjp1a and other tight junction and adherens proteins play important roles in cell-cell adhesion, scaffolding, and forming seals between cells in epithelial and endothelial tissues. In this study, we labeled Tjp1a of zebrafish with the monomeric red fluorescent protein (mRFP) using CRISPR/Cas9-mediated targeted integration of biotin-labeled polymerase chain reaction (PCR) generated templates. Labeling Tjp1a with RFP allowed us to follow membrane and junctional dynamics of epithelial and endothelial cells throughout zebrafish embryo development. For targeted integration, we used short 35 bp homology arms on each side of the Cas9 genomic target site at the C-terminal of the coding sequence in . Through PCR using 5' biotinylated primers containing the homology arms, we generated a double-stranded template for homology directed repair containing a flexible linker followed by RFP. Cas9 protein was complexed with the gRNA before mixing with the repair template and microinjected into one-cell zebrafish embryos. We confirmed and recovered a precise integration allele at the desired site at the C-terminus. Examination of fluorescence reveals RFP cell-cell junctional labeling using confocal imaging. We are currently using this stable line to examine the behavior and interactions between cells during vascular formation in zebrafish.
Topics: Animals; Zebrafish; CRISPR-Cas Systems; Red Fluorescent Protein; Biotin; Endothelial Cells; RNA, Guide, CRISPR-Cas Systems
PubMed: 38621205
DOI: 10.1089/zeb.2023.0096 -
Clinical Genetics Aug 2024CTNND2 encodes δ-catenin, a component of an adherens junction complex, and plays an important role in neuronal structure and function. To date, only heterozygous...
CTNND2 encodes δ-catenin, a component of an adherens junction complex, and plays an important role in neuronal structure and function. To date, only heterozygous loss-of-function CTNND2 variants have been associated with mild neurodevelopmental delay and behavioral anomalies, a condition, which we named Rauch-Azzarello syndrome. Here, we report three siblings of a consanguineous family of Syrian descent with a homozygous deletion encompassing the last 19 exons of CTNND2 predicted to disrupt the transcript. All presented with severe neurodevelopmental delay with absent speech, profound motor delay, stereotypic behavior, microcephaly, short stature, muscular hypotonia with lower limb hypertonia, and variable eye anomalies. The parents and the fourth sibling were heterozygous carriers of the deletion and exhibited mild neurodevelopmental impairment resembling that of the previously described heterozygous individuals. The present study unveils a severe manifestation of CTNND2-associated Rauch-Azzarello syndrome attributed to biallelic loss-of-function aberrations, clinically distinct from the already described mild presentation of heterozygous individuals. Furthermore, we demonstrate novel clinical features in homozygous individuals that have not been reported in heterozygous cases to date.
Topics: Humans; Female; Male; Delta Catenin; Catenins; Alleles; Pedigree; Homozygote; Abnormalities, Multiple; Child, Preschool; Child; Sequence Deletion; Phenotype; Neurodevelopmental Disorders; Consanguinity; Infant
PubMed: 38604781
DOI: 10.1111/cge.14532 -
ELife Apr 2024Collective cell migration is fundamental for the development of organisms and in the adult for tissue regeneration and in pathological conditions such as cancer....
Collective cell migration is fundamental for the development of organisms and in the adult for tissue regeneration and in pathological conditions such as cancer. Migration as a coherent group requires the maintenance of cell-cell interactions, while contact inhibition of locomotion (CIL), a local repulsive force, can propel the group forward. Here we show that the cell-cell interaction molecule, N-cadherin, regulates both adhesion and repulsion processes during Schwann cell (SC) collective migration, which is required for peripheral nerve regeneration. However, distinct from its role in cell-cell adhesion, the repulsion process is independent of N-cadherin -homodimerisation and the associated adherens junction complex. Rather, the extracellular domain of N-cadherin is required to present the repulsive Slit2/Slit3 signal at the cell surface. Inhibiting Slit2/Slit3 signalling inhibits CIL and subsequently collective SC migration, resulting in adherent, nonmigratory cell clusters. Moreover, analysis of ex vivo explants from mice following sciatic nerve injury showed that inhibition of Slit2 decreased SC collective migration and increased clustering of SCs within the nerve bridge. These findings provide insight into how opposing signals can mediate collective cell migration and how CIL pathways are promising targets for inhibiting pathological cell migration.
Topics: Schwann Cells; Animals; Cell Movement; Nerve Tissue Proteins; Mice; Contact Inhibition; Cadherins; Intercellular Signaling Peptides and Proteins; Nerve Regeneration; Locomotion; Cell Adhesion; Signal Transduction; Membrane Proteins
PubMed: 38591541
DOI: 10.7554/eLife.88872 -
Investigative Ophthalmology & Visual... Apr 2024Fuchs endothelial corneal dystrophy (FECD) is a progressive blinding disorder, characterized by increased corneal endothelial excrescences (guttae), corneal endothelial...
PURPOSE
Fuchs endothelial corneal dystrophy (FECD) is a progressive blinding disorder, characterized by increased corneal endothelial excrescences (guttae), corneal endothelial cell loss, and edema. These symptoms are hypothesized to be caused by changes in the extracellular matrix (ECM) and mitochondrial dysfunction in the corneal endothelium. Despite this clinical and biological relevance, a comprehensive animal model that recapitulates all the major disease characteristics is currently unavailable. In this study, we develop such a model to improve our understanding of the signaling pathways involved in the FECD progression and develop strategies for early intervention.
METHOD
To generate a comprehensive FECD model, we generated a double mutant mouse bearing tamoxifen-inducible knockdown of Slc4a11 and the Col8a2 (Q455K) mutation. We performed optical coherence tomography (OCT) and in vivo confocal microscopy using the Heidelberg Retinal Tomography 3 - Rostock Cornea module (HRT3-RCM) on the mice at 5 weeks of age before tamoxifen feeding to establish baseline values for corneal thickness, endothelial cell density, and test for the presence of guttae. We measured these parameters again post-tamoxifen treatment at 16 weeks of age. We collected corneas at 16 weeks to perform histopathology, immunofluorescence staining for tight junctions, adherens junctions, and oxidative stress. We evaluated endothelial pump function using a lactate assay.
RESULTS
The double mutant tamoxifen-fed animals showed the presence of guttae, and displayed increased corneal thickness and decreased endothelial cell density. Endothelial cells showed altered morphology with disrupted adherens junctions and elevated reactive oxygen species (ROS). Finally, we found that stromal lactate concentrations were elevated in the double mutant mice, indicative of compromised endothelial pump function.
CONCLUSIONS
Overall, this mouse model recapitulates all the important phenotypic features associated with FECD.
Topics: Animals; Mice; Fuchs' Endothelial Dystrophy; Endothelial Cells; Disease Models, Animal; Lactic Acid; Tamoxifen; Anion Transport Proteins; Symporters
PubMed: 38587441
DOI: 10.1167/iovs.65.4.18